Electronic relay device



Oct. 21, l941.` H. IAMS ELECTRONIC RELAY DEVICE Filed Dec. 19, 1936 fIIII 4501/.

lll-mf S M Rm. Y m m N 7 SHQ/ 2 K VL IW 2 0 mR 5. |l|| M. -A 2 ....3 byn 2 m 3 I I 3 if im 3. V. f L Z. V. y wld@ .Ul/ WN 4 W .3 M 3 #.Tww. a3f@ M 4 n .5 w 7 7 0 7.1/l 8 Patented Oct. 21, 1941 Enso'raomc maynevica Harley Iams, Berkley Heights, N. J., assignor to RadioCorporation of America, a corporation of Delaware Application December19, 1936, Serial No. 116,689

(Cl. ITS-7.5)

27 Glaims.

This invention relates to an electronic relay device which is controlledby a concentrated electron beam.

More specically the present invention relates t electron tubes andparticularly to electron -tubes of the so-called cathode ray type. Suchtubes may be used for reproducing any electrical phenomena and findparticular use in television systems, both as receiving and transmittinginstrumentalities, in connection with the production of electro-opticalimages, although these devices also are useful in-osciliographinstallations where electrical transients are to be observed.

-With such a type tube or electronic device, and

considering a light producing tube for the Purpose of this description,provision is made whereby the lights and shadows of the subject of whichan image is to'be reproduced are converted into correspondingelectro-optical effects through the conversion of the light of the imageor subject at the point ot tron into electrical signals which then areadapted to control in any desired manner an electron beam in such a typetube in accordance with the varying signal strengths.

In the past, it has been customary in the reproduction ofelectro-optical effects by electronic tubes ofthe cathode ray type todevelop a concentrated electron beam which is projected axially andlongitudinally of the tube so as to impinge upon a luminescent screen toproduce upon the screen both a phosphorescent and a fluorescent efl'ect,with a result that light is developed. The intensity of the light isdetermined, for example, by the electron density per elemental area ofthe impinging cathode ray or electron beam or it is determined by thevelocity with which the impinsing cathode ray beam traverses theluminescent screen or, it is controlled, for example, by thecross-sectional area of the electron beam, that is to say, the beamdensity. as it impinges upon the luminescent screen. The foregoingexamples of spot brilliance control methods are merely illustrativeandare not intended to cover all forms of intensity control for an electronbeam but rather are intended merely as representative of various waysand means which may be and have been adopted for the purpose.

In order to cause the resultant luminous spots to cover a iield of view,that is, to trace a two dimensional image upon the luminescent screen.the developed electron beam or cathode ray is caused to be sweptsimultaneously across the `luminescent screen in two mutuallyperpendicularpathsaccordingtoanydesiredpatternof traversal. The movementof the electron beam limiting and avoiding or cathode ray across theluminescent screen is accomplished by the aid of mutually perpendicularelectrostatic deilecting elds, mutually perpendicular electromagneticdeflecting iields, or a combination of electrostatic and electromagneticdeiiection means. The developed electron beam after being formed issuitably focussed into a sharply defined spot of desired size andcontiguration upon the screen so that as the control beam sweeps thescreen and traverses it according to any desired pattern (such patterns,for example, may be a series of parallel adjacent paths, an interlacedseries of parallel paths, a series of prallel paths alternately changingdirection along the path of a spiral, or many other forms); there willbe produced either the image of some subject from which controllingsignals were initially developed or there will be produced a trace ofsome electrical phenomenon which is to be represented.

With the prior art devices, however, it has been found that a practicallimit of beam current is soon reached without attaining desired optimumspot brilliance with the result that it is very dimcult, if not entirelyimpossible, to increase substantially the brilliance of the resultingluminescent eiiect because the beam current cannot well be increased.This relatively small beam current is the result of the small size ofcathode emitter which is necessary if satisfactory focusing of theresultant cathode ray and a minimum amount of spherical aberration is tobe obtained, and conventional types of large size emitters, which wouldpermit highf beam currents, would thus tendto sacrifice definition forhigh luminosity. The lack of adequate brilliance also is due partly tothe fact that the developed electron beam or cathode ray sweeps theluminescent screen very rapidly and impinges upon each elemental sectionthereof only for` a very short time period for the purpose of producingthe luminescent eect. Not only does the resultant apparent brilliance ofthe luminescent eiect with such types of devices of the prior art failin many instances to reach a desired optimum brilliance. but also thereresults from such types of image producing electronic devices a certainflicker effect and apparent line structure of the luminescent tracewhich is to a greater or lesser degree objectionable and annoying to theobserver.

Therefore, an object of the present invention has been that ofdeveloping ways and means for substantially the ickeriw and linestructure effects in electronic lightl material from a relatively shortto an unusually long time decay period.

A further object of the invention is to provide a method of and ways andmeans for maintaining continuity of electronic bombardment of aluminescent screen over long periods of time and still to provide waysand means for controlling the resultant continuity of the luminescentspots in accordance with some controlling signal.

A further object of the invention is to provide ways and means for'ooding a screen structure. such as the luminescent screen. continuouslywith high velocity electrons to cause light to be developed upon thescreen surface. and then to control the intensity of the developed lightat each elemental area of the luminescent screen structure in accordancewith some controlling signal.

Still other objects of the invention are to provide ways and means forand a method of intensifying substantially the 'brilliance ofelectro-optical eiects developed by electronic bombardment upon aluminescent screen of an electronic device. l

Still further objects and advantages of the invention will immediatelysuggest themselves and become apparent to those skilled. in the art fromreading the following specification and claims in connection with theaccompanying drawing, wherein Fig. 1 illustrates conventionally one formof electronic device for accomplishing the aims and objects of theinvention as above noted;

Flig. 2 represents a 'partial sectional viewv through the insulated gridstructure of Fig. 1 and shows a part of the tube wall:

Flg.3lsaviewsimilartoFig.2butshowsa modied form of insulated gridstructure; and. Fig. 4 is a modification of the arrangement of Fig. 1.

In the preferred embodiment of the present invention, ways and means areprovided for developing within an electronic tube oi' the cathode raytype a signal controlled and focussed electron beam or cathode ray whichis to be directed upon the luminescent screen structure of the tube.This controlled electron beam is then caused to be swept over the entirearea of the luminescent screen structure by suitable electron beamdeveloping means of the character hereinabove mentioned. In addition tothe controlled intensliw electron beam, the luminescent screen structureof the cathode ray tube is also arranged to be subjected to or floodedover substantially its entire area by uncontrolled intensity or, inother words, constant density now, electrons of suitable velocity tocause luminescence from the screen structure. The uncontrolled intensityelectrons are so directed toward the screen structure as to tend tocause normally high brilliance illumination from all elemental areas ofthe screen structure.

As will be therein pointed out in more detail when consideringthe-structural arrangements of the suggested forms for the invention,there is interposed between both electron sources. that is. theuncontrolled source and the electron beam source. a series of electrodeson at least one of which electro-static charges are built up inaccordance with the intensity of the electron of' the controlledelectron beam. These produced electrostatic charges, in turn, controlthe number of uncontrolled electrons which can pass through to theluminescent screen. In this way, there is provided intermediate eachelectron source and the luminescent screen which is to produce lightrepresentative of somesubject, a valve or insulating grid structurewhich controls the total number of electrons which will strike orbombard the luminescent screen at all times. The charges which are builtup on the electrodes intermediate the two electron sources and theluminescent screen are dissipated in the interval between successivetraversals of each elemental area of the electrode intermediate theelectron source and the screen so that the electron beam as it traversesthe electrode serves to modulate, so-tospeak, the uncontrolled electronstream, and thus vary the brilliance of the luminous spots produced.

Referring now more particularly to the drawing for a full and completeunderstanding of certain specinc forms which this invention may assume.there is provided an envelope Il having at one end a tubular portionwhich may be substantially cylindrical or which may be of truncatedconeshaped exterior, and at one end I3, that is, an interior surfacethereof, of this tubular or coneshaped portion there h provided acoating of luminescent material Il on the interior surface. The enlargedsection Il of the envelope is then arranged to merge with the neckportion Il which is also preferably of tubular cylindrical formation andwhich is sealed at one end. Within the neck portion Il of the tubeenvelope, there is arranged the electron gun structure I! for developingan electron beam. 'Ihe gun structure I9 is conventionally illustratedherein and may be of any desired form, for example. the general formshown and described by copending application of John C. Batchelor,Serial No. 584.924 filed January 6, 1932 or, where desired, may be ofother suitable dedgn as taught by Chevallier, Maloif. Epstein andothers.

YIn the conventional form shown, the gun structure comprises an electronsource 2|, known as the cathode. which source may be either directly orindirectly heated. From this source electrons are emitted and drawn intoan electron ray or cathode ray beam by the action of the voltage dropoccurring between the tubular anode 2l and the electron source orcathode 2|. Intermediate the cathode and anode is a grid or controleiectrode Il to which signals are applied in any desired manner. Forconvenience of i1- lustration, the grid or control electrode has beenillustrated as connected to the cathode by way of a variable voltagesource 21 although in actual operation it will be understood that thegrid may be either directly coupled with the output of a suitable signalampliner, such as a television video signal ampliiler, or may becapacitively or transformer coupled to such an amplifier so thatcontrolling signals are applied in the input circuit between. thecontrol electrode and the cathode. The anode I3 is maintained at apositive potential relative to the cathode 2| by way of :he voltagesource conventionally illustrated at- In order to provide a convergingelectrostatic eid which will focus the electron stream issuing throughthe anode 23 into a sharply deiined spot upon the luminescent screen IIor elsewhere in the tube, for example, upon the insulating 'fioeussingcan be obtained.

Also positioned within the tube envelope il and preferably in anoutwardly protruding section thereoi.' out oi the path of the maincathode ray discharge is a second cathode 31 from which an electronstream is emitted. This cathode also may be oi the direct or indirecttype. either type falling clearly within the scope oi .the invention butthe conventional form of direct heater is illustrated merely forconvenience. Electrons emitted from the cathode 31 but not controlled byany signalorthe like as to intensity are acceleratedin the direction otthe screen Il by the application of a suitable positive potential upon agrid or accelerating electrode 3l positioned adjacent the cathode 31 andintermediate the cathode and the luminescent screen l5. Voltages loraccelerating the electron stream issuing from the cathode 41 aresupplied by way of a voltage source 4I.- It will be noted in theillustration of the invention in Fig. 1 that the second cathode I1 ismaintained at a potential corresponding to that of the second anode Ilso that the first cathode 2| is negative with respect to the amasarsecond cathodey 31. Also for the purpose of accelerating the electronsoi' both the controlled stream issuing from the second anode 3i and theundirected stream issuing beyond the grid electrode Il, there ispositioned transversely oi the tube a second accelerating electrode 43.'Ihis electrode 43 is' formed preferably as a metallic ring which restssubstantially upon the inner surface of the tube wall and there isstrung between the edges of this ring-like electrode member a series ofwidely spaced wires.l The electrode 4I is `maintained preferably at thesame `potential relative to the second cathode l1 as menswear-sunsite.trodellsndthelummescentscreenllthereis'midedwhltishereintemedlninaulltodlrid Thh insulated grid l ismainslightly negative with respect to the electron emitng cathodeelectrode Il. The negative potential is obtained by the voltage source4I connectedbetweenthewiresoithegridand the cathode I1.

The insulated grid 44, whose construction is shown more particularly byFig. 2, comprises preferably a ring-like outer supporting element44whichpreierablyrestsagainsttheinner sur- Iacell oithetube wall Il. ber44 has oneedge I! bent or hanged inwardlysothatitcanbesecuredorweldedtothe wires 41 oi the mesh to support themesh. and strung from its outer ring-like member are a 'number of iinemesh wires 4l. The wires forming the mesh 41 tor the insulated gridelectrode 4l, ai'ter the mesh has been suitably rolled and iiattened sothat the wires thereof are substantially iiat, are preferably coatedwith a suitable insulating material 48. The insulating material willthen also coat the nange B2 of ring I4. as shown. 'I'he enamelingprocess may be carried forward to a predetermined degree by dipping themesh-like grid into enamel to provide a coating oi' enamel thereon ofdesired and suitable thickness. 'lhis insulator in the case oi theenamel coating is then baked in suitable manner prior to assembling thetube. When the tube is assembled the mesh and support ring arepositioned within the tube and nt tightly therein. In the glass blowingprocess the tube wall may be heated to cause the glass oi' the tube wallIl to iit tightly about the ring 44 to hold and position it.

According to the construction herein provided, the material which coatsthe wires or mesh 41 oi' the insulated grid is an insulator 4B ofsuitable kind and/or description. 'I'his material is preferably enamelwhich is a coating on the wires of such a thickness and so prepared thatany electrostatic charges which accumulate thereon shall have theproperty of being able to leak away through to the inner conductingwires of the mesh within a predetermined time period. If, for example,the repetition rate of scanning the luminescent screen I5 is at thirtycycles per second, then the charges which accumulate on the enameledmesh 4l oi the insulated grid shall be capable of being substantiallydissipated in a time period Just slightly less than the of a second timeassumed for the cycle of scann sion.

In this connection, it should be noted that the insulated grid 45 isconnected by way of conductor 49 to the high side of the'voltage sourceI5 through the variable biasing source 46 so that the insulated grid 45is, as above stated, slightly negative relative to the cathode I1. Therst anode 23 and the cathode 2l all operate in the assumed form negativerelative to ground potential (that is, potential at point 53) whilecathode 11 and the 'second anode 3i operate at ground potential. Thegrid member 39 and the accelerating electrode 4I operate at a pointpositive relative tothe ground B3 by the voltage supplied from voltagesource 4I.

Interposed between the insulated grid stmoture 4I and the luminescentscreen I5 is an accelerating anode Il which is also in the form of aring which rests against or is supported by the inner suri'ace of thetube envelope Il. Between the outer ring of the acceleratinganode 5Ithere is stretched a coarse wire mesh 53. vThe accelerating anode ismaintained highly positive rela- .tlve to the accelerating electrode 4Iandthe accelerating grid 39 by virtue of the voltage source 55 so thatelectrons passing beyond the insulated grid 45 are accelerated to highvelocities by the voltage gradient existing between the insulated grid45 and the accelerating anode 5I. Since the anode 5I is a coarse wiremesh. as indicated, the electrons passing beyond the insulated grid 45and moving rapidly toward the screen I5, due to the accelerating ileld,pass directly through this anode toward the luminescent screen I5 toimpinge thereupon. The anode 5I can, naturally, be formed of a ne wiremesh and the interstices of the mesh can be accurately aligned with theopenings in the insulated grid mesh 41.

In the area of the tube intermediate ythe accelerating anode 5I and theluminescent screen I5, there is also applied to the inner surface of thetube envelope Il a coating of conducting material 51. This coating maybe what is known in the art under the trade name Aquadag," or it may bea silver coating which may or may not be blackened on its inner surface.Blackening of this silver coating, however, will serve to reduce anyinternal light redections which might otherwise be initiated dile toelectronic bombardment of the luminescent screen I5 by the electronbeams passing through the accelerating anode 5I and the acceleratingcoating 51. Preferably, although not necessarily, the coating 51 and theanode 5I are maintained at the same potential, as indicated. In someinstances the coating 51 may be positive relative to the anode 5I wheregreater velocity of beam impact is desired and, likewise, where a changein focusing, to vary image size for example, is desirable the coatingcan even be negative relative to the anode 5I. Where additionalfocussing of the electrons passing between the accelerating anode 5I andthe luminescent screen structure I5 is desirable, a focussing coil 59wound upon a yoke 5I may be arranged to surround the end of the tubeadjacent the luminescent screen and inter# mediate the screen and theaccelerating anode. This focussing coil 59 may be energized withsubstantially constant voltage energy from a direct current supplymeans, where desired, so that a substantially constant intensityelectromagnetic field is developed to concentrate the electron streamupon the luminescent screen. It is, however, to be understood thatelectrostatic focussing of the impinging electrons on the luthat suvcndenectmg nelds may be provided at any point along the tube axis as maybe desirable.

' It is suggested thatsuitable deilecting means ybe positioned betweenthe rst anode 23 andthe second anode 3|. Such deflecting nelds, as abovenoted, may be developed by the use of purely electrostatic or purelyelectromagnetic means or a combination of both. Suitable energizingvoltages or currents are applied to the deiiecting means in order thatthe electron beam projected longitudinally of the tube 'shall be causedto sweep across the insulated grid structure 45 according to any desiredpattern of traversal depending of course upon the wave formation of theelectrical energy supplied to the deecting means.

In the operation of a tube of the type shown by Fig. 1 of the drawing.for example, the beam minescent screen may be obtained by approxiymately selecting and designing the electrodes 51 and 5I and making anappropriate selection of the voltages applied thereto. For example,anode 5| may then be a metal ring having a length and diameter equalsubstantially to the internal diameter of the tube, and the coating 51or the inner surface of the tube envelope may have a length equal totwice the tube diameter of electrons resulting from the emittedelectrons from the source 2I being drawn into a beam by the first anode23 and the second anode 3l are caused by the deflecting ilelds (notshown) to sweep the insulated grid structure 45 in the desired pattern.Signals areapplied to the control grid 25 to modulate the developedelectron beam so that the electron beam which impinges upon theinsulated grid structure 45 shall be a beam controlled in intensity inaccordance with a signal to be represented electro-optically on screenI5 at the end Il of the tube. As the controlled intensity electron beamscans the insulated grid structure 45, a pattern of charges representingthe image to be produced on screen I5 is left on the surface of theinsulator 45 in the wire mesh 41 of the insulated grid 45. Thiselectrostatic charge, like the impinging beam, is proportional to theintensity of the electron stream flowing longitudinally oi' the tube andwill substantially leak away under normal operating conditions, as abovenoted, during the time interval between successive scannings of the sameelemental area of the insulated grid structure 45. Simultaneously, thereis being produced from the electron source 31 and accelerated by thegrid 39 and the accelerating electrode 43 toward the insulated gridstructure 45 a second stream of electrons having an area substantiallyequal to the internal diameter of the tube and high density.v

This latter-named stream of electrons is proiected as a dispersingstream of electrons, although of high density, which normally oods theinsulated grid structure 45 and would normally tend to penetrate equallyall the interstices of the mesh 41 except for the negative potentialapplied thereto by-the source 45 which biases the insulated gridsubstantially to cutolf.

The intensity controlled electron stream issuing from anodes 2J and 3|is, however, scanning the mesh 41 of the insulated grid 45 and impingesthereupon at a relatively high impact velocity. The controlled intensityelectron beam when striking the insulated (enamel) surface 48 of theinsulated grid 45 causes secondary electrons to be emitted from theimpact surface. 'I'he number of secondary electrons released by theimpact of the scanning beam being greater than one secondary electronper arriving primary electron which causes the 'enamel surface toacquire at diil'erent elemental areas thereof as it is scanned apositive potential relative to the wires 41 upon which the enamel orinsulating coating is supported. There is thus developed between thesurface of the enamel or insulator Il and the supporting mesh conductor`Il and electrostatic charge which, as above described, will besubstantially dissipated due to leakage within the time period betweensuccessive traversals oi' the same elemental motion or area ofthemeshbythescanningelectronbeam.

The magnitude of the electrostatic charge developed is a function of theelectron density of the signal controlled scanning beam whose electrondensity varies in accordance with the magnitude of the control signalapplied to the control grid It.

Thus. with the signal controlled and focussed cathode ray scanning beamtraversing the inllilatedgrid I5, the biasing eil'ect of source 40 onelemental areas of the insulated grid Il is overcome by the positiveelectrostatic charges produced on the enamel or insulating surface Il bythe controlled intensity scanning beam. Whenever the insulators orenameled areas 48 are at a positive potential relative to the abovementioned cut-olf potential, the high density electron iiow from thesource 31 will penetrate the interstices of the insulated grid 4l and beaccelerated toward the luminescent screen Il. In accordance with theabove explanation of operation, which it is believed is the theory uponwhich the device operates, which the signal controlled scanning electronbeam traverses each elemental area of the insulated grid Il with greatrapidity to leave the elemental areas positively charged, as abovespecified, the high density electron stream from source 31 continues toiiow through the mesh 41 toward the luminescent screen Il for anappreciable time period subsequent to the time when the scanning beamleaves each elemental area of the insulated grid 4I. Thus. theelectro-optical image produced upon the luminescent screen II by theelectron beam impact is of greatly increased optical brilliance.

While the above is the preferred method of operation. it is alsopossible to consider that the device may operate in such a manner thatthe scanning 'electron beam releases less secondary electrons from theinsulating surface I .of the insulated grid l! at each point of impactthan there are arriving primary electrons. This would be particularlyapplicable where the insulated grid structure ll has the mesh wires I1coated with a material of low secondary emitting properties, such ascarbon. In such event the wires l1 would be enameled and then theenameled surface coated with isolated particles Il of the carbon. Ihisform of the insulated grid is shown particularly by the sectional viewof Fig. 3. although it'will be appreciated that the device shown by Fig.3 may operate as a high secondary emission type. and in accordance withthe above theory, where the isolated coating material is, for example,oxidized silver particles coated with caesium.

Where less secondary emission is assumed. as

with the particle coating of Fig. 3, being in the so as to strike theluminescent material It with substantial velocity and to cause therebylight vto be emitted or developed at the screen. However, in accordancewith the electrostatic f charges acquired by the insulated gridstructure yous elemental sections thereof by amounts which areproportional to the intensity of the electron beam impinging thereupon.Thus, the insulated grid acts as a control grid, so-to-speak, to controlthe final effect of the electronic emission from the lelectron source31. The insulated grid 48 thus varies the number of electrons from theuncontrolled source 31 which are able to penetrate the insulated grid45. In this way, the luminescent screen I5 is dark or light over variouselemental sections in accordance with the intensity of the electron beamfrom the source 2|, but the luminescence of the screen isl maintaineddue to the continuity cf the controlled electron stream thereupon sothat the luminescent screen is excited substantially all the time numberof electrons from a dii'fusely radiating' emitter which strike theluminescent screen behind the controlling element.

In a modiiled form 'of the arrangement shown by Fig. 4, structurally thesystem is substantially form of carbon. the strongly negative neld due p'to low secondary emission from the carbon parveloped by the scanningbeam impinglng upon those portions of the enamel not coated withthecarbon For thecaseoflowsecondaryemislion, it is possible to omit thebiasing source II so that the uncontrolled intensity electrons developedfrom the source Il would normally beacceleratedbytbefielddevelopedbetweenthe as shown by Fig. 1 except thatthe luminescent screen is tilted with respect to the position shown byFig. l, and electrode members 45 and 43 are supported closely -adjacenteach other and the screen. In this form, the luminescent screen isformed upon an insulating sheet, such as the mica 'base 1I, which hasstretched across the surface thereof adjacent the electron sources aconducting wire mesh 'I3 (shown as dots on the surface). The luminescentmaterial 10 is placed upon this side of the insulating sheet 1I and thelight developed by beam impact is viewed through the insulating sheet orbase 1i. In practice it hasbeen found that an insulating base, such asthe mica sheet 1I, may have substantial rigidity even though thethickness is of the order of 0.005 inch and accordingly substantially nolight absorption will be found. In this form of the arrangement,separate mica spacer elements in the form of rings 15 separate theaccelerating anode in the form of the wire mesh 'I3 having waysconductors 'Il and woof conductors 16 from the insulated grid I5, andthe accelerating electrode Il is separated from the insulated grid 4l byan additional mica spacing ring 11. Other forms of spacing rings and thelike may be used Awhere desired, and such may be lava, bakelite,

and other forms. The entire assembly may be held in place by slightlycrimping the tube wall. as at 8l, when the tube is assembled. As theelectrons from the uncontrolled source impinge upon the luminescentscreen structure and are controlled in the manner described inconnection with Figs. 1 through 3, the luminescent material Il upon theplate structure becomes both luxlnescent and phosphorescent. This formof device is frequently desirable because the construction permits amore uniform distribution accelerating anode Il and the insulated gridIl `of the high density uncontrolled electron stream from source 31 overthe insulated grid structure I3. With, however, the luminescent screenstructure tilted at an angle with respect to the direction ofpropagation of the controlled electron beam, it is then usuallydesirable to correct for the so-called keystone distortion which resultsnormally due to the inclination of the plane upn which the imageappears. Such forms of keystone correction are well known in the art andneed not herein be explained in detail.

The foregoing description has considered only electron density variationof the scanning `electron beam as the controlling factor in producingthe electrostatic charge e'ects. However, it is desirable also toconsider constant electron densities with variable velocities of vtheelectrons impact upon the insulated grid surface or of variable velocitytraversal of the insulated grid structure by the scanning beam. Thesetwo variable velocity conditions require either a constant velocity ofimpact of the scanning beam on the insulated grid l witha variable rateof traversalor a constant rate of traversal of the insulated grid l5 bythe scanning beam and a variable velocity of impact. For the rst oi'these conditions, the received video signals which are to beelectro-optically reproduced are caused to control or modify the actionof the beam deecting system, for example, as taught by Rosing (see U. S.1,161,734 for example). In the second form of velocity modulation (i. e.control of velocity of impact), the received signal could be applied inseries with vvoltage source 35 so as to change the potential of thecathode 2| relative to the insulated grid l5. While this might cause aslight defocussing of the scanning beam upon the insulated grid 45 vsuchdefocussing would not be at all serious. However, defocussing of thescanning beam can be minimized by connecting the second anode 3|directly to the positive ter'- minal of source 35 (rather than tocathode 31 as shown by Fig. 1) and then introducing the videosignalintermediate the point of connection of the second anode 3| to thesource 35 and the cathode 31 which `is normally maintained at the samepotential as the anode 3| relative to the cathode 2 I.

In some instances, it may be desirable to operate the cathode -31slightly positive relative to the anode 3| in order to prevent anycurrent dow from anode 3| to cathode 31 and also to permit moreeffective directing of the diffused high mesh 41 of the insulated gridl5 and, for example, there may be substituted for the suggested enamelother materials such as aluminum-oxide (A1201), calcium-fluoride (CaF),mica, or any other material having substantial insulating properties. li

In some @ein it may be desirable to replace the luminescent material I3by other forms of recording surfaces which may include a photographici'llm or plateresponsive to electronic energization as well as any formof insulating base upon which previously dusted particles are displacedand any form of metal surfacewhich is changed in color by electronicimpact.

Further, whiley suggested operating voltages and conditions have beenillustrated and suggested by the showings of Figs. l and 4 it is, ofcourse. to be appreciated that the values chosen are merly illustratedby way of example since, in practice, wide variations may be founddesirable. Therefore, all such'values are to be regarded solely asillustrative and not in any sense ylimiting density electron streamissuing from cathode 31 I, upon the insulated grid. This may be done inFig. 1 by connecting a biasing source (not shown) in the line 33 withthe positive terminal point connecting with cathode 31. Where variationsin impact velocity are relied upon for control, this biasing source isconnected in series with the video signal input between the source 35and the cathode 31 in such manner that cathode 31 is at a positivepotential relative to anode 3|.

While the invention has been described particularly in its relation to atelevision system, it finds application in mam other fields, forexample, in oscillograph apparatus. In such usage it is frequentlydesirable to maintain the visible phenomena upon the luminescent screenI5 for a longer period of time in order that more than a single waveformation `may be observed. In such use the time constant of the system,that is, the period of charge leakage from the insulaf'd grid 45 may belonger or shorter than Hove described. 'I'his is done by varying thespecific resistance of the insulating coating 48 on the Many other and"varied modications of the invention are, of course, possible withoutdeparting -from the spirit and scope as it is hereinabove explained. Itis, therefore, believed that the invention should be construed broadlyin the light of the foregoing disclosure and that any and allmodifications as fall clearly within the spirit and scope of the hereinappended claims may be used as desired.

Having now described the invention, what is claimed as new and what isdesired to secure by Letters Patent is the following:

1. The method of producing electro-optical effects which comprisesproducing a bidimensional electrostatic image of a subject, varying theintensities of the electrostatic charge of elemental areas of theelectrostatic image in accordance with signalling modulation anduniformly flooding the signal modulated electrostatic image with anelectron flow to produce a magnied intensity electronic duplicate.

2- An electronic image reproducing system comprising a bidimensionalelectrostatic charge collecting electrode member to store an image intwo coordinates, means for directing a substantially spatially uniformelectron flow through the charge collecting electrode member, anelectron responsive target element positioned to receive the electronsprojected through the charge collecting electrode member, and signalcontrolled means for electronically controlling the electronic flo'wthrough said member to said target elemen 3. In a cathoderay imageproducing system, means to produce` a sharply concentrated electronbeam, an insulated grid structure of substantially image area interposedin the path of said beam, means for signal modulating the concentratedelectron beam, means for causing said electron beam to sweep saidinsulating grid structure in two dimensions to Vproduce thereupon atvarious elemental areas varying intensity electrostatic charges varyingin accordance with the intensity of the controlled electron beam duringtraversal, means for producing an uncontrolled intensity and constantdensity electron ow for flooding said insulated grid structure andpermeating the same in varying degrees dependent upon the magnitude ofsaid produced charges, and means for accelerating the permeatingelectrons for producing electron activated representaaasaeovilomofthavariations of chargeonsaid insu- 4. The method of controllingelectronic actiration o! an electron target which comprises the steps otprojecting toward the target a'signal controlled concentrated electronstream, simultaneously projecting a substantially spatially uniformelectron stream toward the target to flood normally the entire target.and controlling the electron stream reaching the target at a surfacemtermediate the target and the source of each electron stream by thesignal controlled electron stream.

5. In an electron tube, a bidimensional gridv structure adapted to haveproduced repeatedly over the surface thereof electrostatic charges ofvarying magnitude to represent light values of related elemental areasof a bidimensional subject varying between black and white and also ofvrylnl decreasing magnitude measured by the electrode, flooding theentire area of the charge collecting electrode by the disperselyprojected electrons, and directing the dispersely projected timeinterval between successive repetitions of the charges, means to noodthe grid structure area with an uncontrolled substantially constantinlensity electron flow, and means to produce from the uncontrolledelectron now, as modified by the electrostatic charges, an electronicduplicate of the instantaneous electrostatic charges in mag-- nliledintensity. f

6. The method of controlling electronic activation o! a bidimensionaltarget which comprises the steps of projecting toward the target a con-Vcentrated electron ray, controlling the intensity of the projectedconcentrated electron ray by sigmeable charge collecting electrode, anelectron' source for producing a focused `beam of electrons, and asecond source of ilooding electrons, the method of controlling theenergization of the luminescent surface which includes the steps ofsweeping the charge collecting electrode in two directions of traverseby the focused electron beam. producing charges varying over eachelemental area of the charge collecting electrode in accordance with theelectron density of the sweeping electron beam, substantially uniformlyi'iooding the entire area of the charge collecting electrode by thedispersely projected electrons and directing the dispersely projectedelectrons through the charge collecting electrode to the luminescentsurface in accordance with the magnitude of the charge produced upon thecharge collecting electrode.

8. In an electronic device wherein there is provided an electronresponsive signal utilization surface. an electron permeable charge-collecting electrode, an electron source to produce an electron beam,and a second source of dispersely projected electrons of substantiallyuniform cross sectional area density, the method of controlling thevenergization of the signal utilization surface which includes the stepsof sweeping the charge collecting` electrode by the electron beam,controlling the number of beam electrons reaching each unit area of thecollecting electrodes, producing from the electrons reaching the collecting electrode varying charges over each elemental electrons through thecharge collecting electrode to the signal utilization surface inaccordance with the magnitude of the charge produced upon the chargecollecting electrode.

9. In a system for producing observable effects upon a luminescentscreen having positioned adjacent thereto an electron permeable controlmember, the method of intensifying the resultant luminescent transientwhich comprises the steps of projecting a focused controlled intensityelectron beam upon the electron permeable control member, producing uponthe electron permeable control member surface a series of electrostaticcharges varying in accordance with variation in the intensity of theprojected electron beam so that the charges are proportional to thespatial illumination of an object, flooding the electron permeablecontrol member with uncontrolled intensity constant density electronstream, varying the uncontrolled intensity constant density electronstream permeating the electron permeable control member in accordancewith the charges produced thereupon by the controlled intensity electronbeam, accelerating the electron flow permeating the electron permeablecontrol member, and producing luminous effects from the acceleratedelectron flow.

l0. In a system for reproducing transients on an electron responsivescreen having positioned adjacent thereto an electron permeable controlmember composed of a plurality of mutually insulated elemental areashaving a predetermined leakage therebetween. the method of intensifyingthe resultant transient effect which comprises the steps oi' ooding theelectron permeable control member with a stream of constant densityelectrons adapted to pass therethrough, acceleratingv the permeatingelectron stream in the direction of the screen for producing indicationsthereupon, developing a signal controlled concentrated electron beam,projecting the signal controlled concentrated electron stream toward theelectron permeable control member, tracing the concentrated electronbeam across the sur- Y electron quantity. of the flooding electronstreanM area o! the collecting electrode in accordance 76A passing theelectron permeable control membei per elemental area in accordance withthe mag-4 nitude of the electrostatic charge produced by theconcentrated beam, and dissipating the charge induced upon the electronpermeable control member by the concentratedelectron beam by way oi theleakage path between the elemental areas of the electron permeablecontrol member during the time interval between successive impacts ofthe concentrated electron beam at identical elemental areas.

1l. In a system for reproducing transients on an electron responsivescreen having positioned adjacent thereto an electron permeable controlmember composed of a bidimensional array of a plurality of mutuallyinsulated elemental areas having a predetermined leakage therebetween,the method of intensifying the resultant transient effect whichcomprises the steps of flooding the electron permeable control memberwith a stream of substantially constant density electrons adapted topass therethrough. accelerating the permeating electron stream in thedirection oi the screen for developing luminous effects thereupon due toimpact, scanning the electron permeable member by a signal controlledscanning beam to produce electrostatic charges therei'romwhich arerepresentative of a subject, and controlling the magnitude of ,theilooding electrons passing through elemental sections of the electronpermeable member in accordance with the electrostatic charge thereatdeveloped. s

a 12. The method of producing images which comprises the steps ofdeveloping a signal controlled electron beam, producing an electrostaticimage of a subject under the control of said beam,

substantially all elemental areas of said image being represented aselectrostatic charges with the magnitudes of charge for anypredetermined light valve capable of varying with time, uniformlyiiooding the electrostatic image with electrons for producing from allinstantaneous conditions of the electrostatic image a current image' ofan intensity substantially magnified with respect to the currentstrength required produce the electrostatic image.

13. A cathode ray tube comprising an envelope containing a luminescentscreen defining a picture area. an apertured grid adjacent and parallelto said screen, said grid' being conductiveand covered with a layer ofcharge retaining material, an electron gun including a cathode and ananode cooperating therewith to define an-electron beam of elementalcross-section, a second electron gun comprising a cathode and an anodecooperating therewith to define an electron beam of picture areacross-section, both of said guns being positioned to direct electronsemitted therefrom on said screen through' said grid with said beam ofpicture area cross-section registering with said picture area of saidscreen, and deflection means associated solely with said i'lrst anodeand cathode.

14. An electron image amplifier comprising an envelope containing meansfor generating a spatially uniform electron flow, an apertured member inthe path of said flow, means for producing on said member a charge imagespatially representing the spatial illumination of an object, and meansfor collecting electrons in elementary areas of the electron streampassing through said apertured member.

15. In an electron tube an apertured insulated grid, an electronemitting element to emit a spatially uniform flood of electrons, meansto project the emitted ilood ofY electrons through said apertured grid,means to produce on said apertured grid a bidimensional electrostaticcharge image representative of a picture. a target element located onthe side of said apertured grid opposite the source of ooding electrons,and means to' focus electrons passing through said grid upon saidtarget.

16. In an electron tube an apertured insulated grid, a thermioniccathode to emit a spatially uniform flood of electrons, means to projectthe thermionically emitted electrons through said apertured grid, meansto produce on said apertured grid a bidimensional electrostatic chargeimage representative of a picture, a target electrode located on theside of said apertured grid opposite said thermionic cathode, and meansto focus electrons passing through said grid upon said target.

17. Acathode ray tube reproducer comprising means for projecting a mainbeam of electrons towards an area upon which a picture is to bereproduced so as to bombard the whole picture area, an electrode whichis permeable to said main beam interposed in the path of said main beam,means obliquely positioned with respect to the means for projecting themain beam of electrons for .scanning said electrode by a signalcontrolled concentrated cathode ray beam. whereby said electrodereceives electron density controll0 ling potentials at diiferentelemental areas thereof. y y

i8. A cathode ray tube comprising means for continuously projecting amain beam of electrons, a perforated electrode interposed in the path ofsaid main beam, an electron gun obliquely positioned with respect to themeans for projecting the main beam of electrons for projecting aconcentrated cathode ray beam upon said electrode, means adapted tocause said concentrated beam to scan said electrode and means adapted tobe operated by image signals for eii'ecting modulation of theconcentrated scanning beam, said interposed electrode being soconstructed that the potentials of ythe di'erent elemental areas thereofmay be controlled by the scanning cathode ray beam whereby the electronintensity in the corresponding parts of the main beam passed by saidelectrode may be correspondingly controlled.

19. Apparatus as `claimed in claim 18 and wherein the interposedelectrode which is scanned is aperforated electrode constructed toconstitute a mosaic oi elemental condensers.

20. In a system for producing observable transients on a luminescentscreen having positioned y adjacent thereto an electron permeablecontrol member, the method of intensifying the resultant luminescenttransient which comprises the steps of ooding the electron permeablecontrolmember with a beam of electrons adapted to pass therethrough toproduce upon the luminescent screen an observable indication, producinga concentrated electron beam and projecting the same at an oblique anglewith respect to the ooding beam of electrons toward the electronpermeable control member, tracing the concentrated electron beam acrossthe surface of the electron permeable control member -so as to scan thesame according to a predetermined pattern of traversal, producing fromthe scansion of the elec- Y 21.v In a system for producing observabletransients on a luminescent screen having positioned adjacent thereto anelectron permeable control member composed of a plurality of mutuallyinsulated elemental areas having a predetermined leakage therebetween,the method of intensifying the resul-tant luminescent transient whichcomprises the steps of flooding the electron permeable control memberwith a beam of electrons adapted to pass therethrough to produce uponthe luminescent screen an observable indication, producing aconcentratedelectron beam and projecting the same at an oblique angle with respectto the ooding beam of electrons toward the electron permeable controlmember. tracing the concentrated electron beam across the surface of theelectron permeable control member so as to scan the same according to apredetermined pattern 75 oi' traversal, producing from the scansion ofthe electron permeable control member electrostatic charges thereupon,controlling the electron density of the flooding electrons passing theelectron permeable control member per elemental area in accordance withthe magnitude of the electrostatic charge produced by the concentratedbeam, and dissipating the charge induced upon the electron permeablecontrol member by the concentrated electron beam by way of the leakagepath between the elemental areas of the electron permeable controlmember during the time interval between successive impacts of theconcentrated electron beam at identical elemental areas.

22. The method of reproducing images upon a target which comprises thesteps of directing a broad beam oi' electrons toward the luminescentscreen, said broad beam of electrons having substantially constantelectron density per unit area in a plane transverse to the axis of saidbeam, modifying the electronic density oi" said elemental areas of saidbroad beam of electrons by interposing an electric charge replica of theimage to be reproduced, and impacting the modiiied beam upon the targetto reproduce a picture.

23. Ihe method of reproducing images upon a luminescent screen whichcomprises the steps of obliquely directing a broad beam of electronstoward the luminescent screen, said broad beam of electrons havingsubstantially constant electron density per unit area in a planetransverse to the axis of said beam, modifying the electronic density ofsaid elemental areas of said broad beam of electrons by interposing anelectric charge replica of the image to be reproduced, and impacting themodified beam upon the luminescent screen to reproduce a picture.

24. 'I'he method of reproducing nuages which comprises the steps ofreceiving electrical signals representative of an image to bereproduced, ooding an electron sensitive surface with a broad beam ofelectrons, directing a narrow beam of electrons toward said surface,controlling the spatial position of said narrow beam by locallygenerated oscillatory energy. controlling the intensity of said narrowbeam of electrons by the received signals, interposing under theinfluence of the controlled intensity electron beam an electric chargeimage of the image to be reproduced and utilizing the interposedelectric charge to regulate the number of electrons per elemental areaof said broad beam reaching said surface and thereby reproduce apicture.

25. Apparatus for reproducing images comprising a luminescent screen,means for directing a broad beam of electrons of substantially constantdensity per unit cross-sectional area toward the luminescentscreen.,said broad beam of electrons having substantiaLfsonstantelectron density per unit area, means for modifying the electronicdensity of said elemental areas oi' said broad beam of electrons byinterposing an electric charge replica of the image to be reproduced,and means for impacting the modified beam upon the luminescent screen.

26. Apparatus for reproducing images comprising a luminescent screen,means for obliquely directing a broad beam of electrons of substantiallyconstant density per unit cross-sectional area toward lthe luminescentscreen, said broad beam of electrons having substantially constantelectron density per unit area, means for modifying the electronicdensity of said elemental areas of said broad beam of electrons byinterposing an electric charge replica of theimage to be reproduced, andmeans for impacting the modified beam upon the luminescent screen.

27. Apparatus for reproducing images comprising an electron sensitivesurface, means for receiving electrical signals representative of animage to be reproduced, means for flooding said electron sensitivesurface with a broad beam of electrons of substantially constant densityper unit cross-sectional area, means for directing a narrow beam ofelectrons toward said surface, means for controlling the intensity of idnarrow beam of electrons by the received m ls, and means for utilizingthe controlled beam to produce an electric charge image oi. the image tobe reproduced, and means to regulate the number of electrons perelemental area of said broad beam reaching said surface under theinuence of the charge image.

HARLEY IAMS.

